Restrictive mitral annuloplasty for functional mitral regurgitation: acute hemodynamics and serial echocardiography

Clinical Outcomes Following Durable Mitral Valve Repair for Ischemic Mitral Regurgitation

BACKGROUND

This study aimed to clarify the incidence and determinants of postoperative adverse events in patients with ischemic cardiomyopathy who achieved long-term durable mitral valve repair.

METHODS

Between 1999 and 2015, 166 patients with chronic ischemic mitral regurgitation (MR) and left ventricular (LV) ejection fraction ≤40% underwent restrictive mitral annuloplasty. During follow-up (65±34 months), echocardiographic assessments were performed 809 times (mean, 4.9±2.4 times) and 20 patients who had developed postoperative recurrent MR (≥moderate) were excluded. Finally, 146 patients (68±9 years) whose MR was well controlled over time were included.

RESULTS

A total of 61 mortalities and/or 27 readmissions for heart failure were observed in 76 patients (52%). Among hospital survivors, age (adjusted hazard ratio: 1.05; P=0.001), and estimated glomerular filtration rate (adjusted hazard ratio: 0.61; P=0.001) were identified as independent predictors of long-term mortality and/or readmission for heart failure. The degree of LV function recovery after surgery was comparable between patients with and without adverse events. However, the former group showed greater values for systolic pulmonary artery pressure, tricuspid regurgitation severity, inferior vena cava dimension, and plasma brain natriuretic peptide level throughout the follow-up period (group effect p<0.05 for all).

CONCLUSIONS

Approximately 50% of patients died or were hospitalized for heart failure even in the absence of recurrent mitral regurgitation during the 5-year follow-up, indicating that durable mitral repair does not always lead to favorable clinical outcomes. The adverse events might be related to volume overload secondary to impaired renal function and less favorable pulmonary hemodynamics.

How does severe functional mitral regurgitation redefined by European guidelines affect pulmonary vascular resistance and hemodynamics in heart transplant candidates?

OBJECTIVE

Increased pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) are important prognostic factors in patients with heart transplantation (HT). It is well known that severe mitral regurgitation increases pulmonary pressures. However, the European Society of Cardiology and the 6th World Symposium of pulmonary hypertension (PH) task force redefined severe functional mitral regurgitation (FMR) and PH, respectively. We aimed to investigate the effect of severe FMR on PAP and PVR based on these major redefinitions in patients with HT.

METHODS

A total of 212 patients with HT were divided into 2 groups: those with severe FMR (n=70) and without severe FMR (n=142). Severe FMR was defined as effective orifice regurgitation area ≥20 mm2 and regurgitation volume ≥30 mL where the mitral valve was morphologically normal. A mean PAP of >20 mm Hg was accepted as PH. Patients with left ventricular ejection fraction ≤25% were included in the study.

RESULTS

The systolic PAP, mean PAP, and PVR were higher in patients with severe FMR than in those without severe FMR [58.5 (48.0-70.2) versus 45.0 (36.0-64.0), p<0.001; 38.0 (30.2-46.6) versus 31.0 (23.0-39.5), p=0.004; 4.0 (2.3-6.8) versus 2.6 (1.2-4.3), p=0.001, respectively]. Univariate analysis revealed that the severe FMR is a risk factor for PVR ≥3 and 5 WU [odds ratio (OR): 2.0, 95% confidence interval (CI): 1.1-3.6, p=0.009; and OR: 3.2, 95% CI: 1.5-6.7, p=0.002]. The multivariate regression analysis results revealed that presence of severe FMR is an independent risk factor for PVR ≥3 WU and presence of combined pre-post-capillary PH (OR: 2.23, 95% CI: 1.30-3.82, p=0.003 and OR: 2.30, 95% CI: 1.25-4.26, p=0.008).

CONCLUSION

Even in the updated definition of FMR with a lower threshold, severe FMR is associated with higher PVR, systolic PAP, and mean PAP and appears to have an unfavorable effect on pulmonary hemodynamics in patients with HT.

Detrimental effects of elevated transpulmonary gradient on outcomes following restrictive mitral annuloplasty in patients with pre-existing pulmonary hypertension

Background

This study retrospectively examined the association between elevated trans-pulmonary gradient (TPG), which reflects pre-capillary contribution to pulmonary hypertension (PH), and postoperative pulmonary hemodynamics and outcomes following restrictive mitral annuloplasty (RMA) in patients with pre-existing PH.

Methods

Pre- and postoperative (1 month) cardiac catheterization was performed in 64 patients with severely impaired left ventricular function (i.e., ejection fraction ≤40%) and pre-existing PH (mean pulmonary artery pressure (PAP) ≥25 mmHg) who underwent RMA. Patients were segregated into two groups: low TPG (≤12 mmHg) and elevated TPG (>12 mmHg). The mean follow-up period was 54±27 months. The primary outcome seen was a change in pulmonary hemodynamics after RMA; secondary outcomes were composite adverse events, including all-cause mortality and readmission for heart failure.

Results

Compared to the low TPG group, patients in the elevated TPG group were more likely to show a postoperative mean PAP of ≥25 mmHg (84% vs. 38%), TPG of >12 mmHg (79% vs. 11%), and pulmonary vascular resistance of ≥240 dynes/sec/cm⁻⁵ (84% vs. 6.7%) (all P<0.001), although both groups showed comparable degrees of mitral regurgitation improvement. Serial echocardiography demonstrated that Doppler-derived systolic PAP, which once decreased in both groups, remained stable in the low group while steadily increasing in the elevated group (group effect P<0.001). Patients with elevated TPG had lower freedom from composite adverse events (5-year, 20% vs. 70%, P=0.003). After adjusting for baseline covariates, the elevated TPG was independently associated with increased risk of adverse events (adjusted hazard ratio 2.9, 95% CI: 1.2–6.9, P=0.017).

Conclusions

Elevated TPG negatively affects postoperative pulmonary hemodynamics and late outcomes in patients with advanced cardiomyopathy and pre-existing PH who have undergone RMA. These findings suggest that the assessment of TPG should be included in post-RMA risk stratification.

Midterm outcomes of chordal cutting in combination with downsized ring annuloplasty for ischemic mitral regurgitation

PURPOSE

We describe midterm outcomes after division of secondary chords (chordal cutting) combined with downsized ring annuloplasty for ischemic mitral regurgitation (IMR).

METHODS

We compared the clinical outcomes in patients who underwent chordal cutting with downsized ring annuloplasty (CC-group, n = 15) and those who underwent conventional ring annuloplasty only (Conventional-group, n = 35) for IMR. Follow-up was complete in all patients. The median follow-up time was 4.1 years.

RESULTS

Thirty-day mortality was 0% in CC-group and 20% in Conventional-group. The overall survival rate at 5-year was 80.8% ± 12.6% in CC-group and 61.7% ± 8.4% in Conventional-group (Log-rank, p = 0.145). The freedom rate from valve-related events at 5 year was 84.6% ± 10.0% in CC-group and 65.3% ± 10.1% in Conventional-group (Log-rank, p = 0.213). Recurrence of severe mitral regurgitation was revealed in 3 patients of CC-group. Preoperative tenting height was the significant predictor of mitral regurgitation recurrence. In CC-group, the mean left ventricular ejection fraction was 38.0% ± 14.0%, which was similar to the preoperative value of 40.0% ± 13.2% (p = 0.349).

CONCLUSIONS

Chordal cutting with downsized ring annuloplasty for IMR is a simple method and provides satisfactory early outcomes. However, it carries with high recurrence of MR especially for patients with high tenting height.